MX2007015680A

MX2007015680A - Magnetic composite materials and articles containing such.

Info

Publication number: MX2007015680A
Application number: MX2007015680A
Authority: MX
Inventors: Eric Vignola; Richard J Burns
Original assignee: Nova Chem Inc
Priority date: 2005-06-30
Filing date: 2006-06-29
Publication date: 2008-02-21
Also published as: WO2007005487A2; KR20080028468A; AU2006266070A1; JP2009500249A; EP1907203A2; CN101557930A; US20080129462A1; WO2007005487A3; CA2611792A1

Abstract

Composite materials that include a resin containing a polymer obtained by polymerizing a monomer mixture that contains at least one polymerizable monomer and a magnetic material, where the composite material can be used to make sheet stock and articles, such as storage containers. The composite materials can be made by mechanical milling the magnetic material into the resin or by using bulk, suspension, emulsion, mini-emulsion or micro-emulsion polymerization techniques where the resin is formed in the presence of the magnetic material. Articles made of the composite material can be used in a method of deterring theft of an article which includes providing the above-described container, applying a magnetic field to an interrogation zone, causing movement of the container into the interrogation zone, and detecting a magnetic response resulting from the container moving into the interrogation zone.

Description

MAGNETIC COMPOSITE MATERIALS AND ARTICLES QU? THEY CONTAIN FIELD OF THE INVENTION The present invention is directed to composite materials having magnetic properties, to the sheets containing such composite materials, and to articles, in some cases, storage containers, containing the magnetic composite materials. BACKGROUND OF THE INVENTION A number of passive data labeling systems are already known in the art. As an example, the data labels referred to as bar codes, are based on printed line configurations that are read optically, are well known. Barcode systems are low cost, typically requiring only ink and paper. Readers are also relatively inexpensive, typically using scanning laser beams. For the vast majority of applications, the only real disadvantage of bar code systems is the need for an observation line between the reader and the label. For applications where the observation line is not possible, systems have been developed that do not use optical transmission. One such system employs magnetic induction for the coupling between the tag and the electronic interrogator devices. These Ref.188314 applications typically operate with alternating magnetic fields in the frequency range of 50 kHz to 1 MHz, and generally employ integrated electronic circuits ("chips") to handle the transmission and reception functions, and to provide storage and manipulation of data . To avoid the need for a battery, the energy for the chip is obtained by rectifying the interrogation signal received by a coil of an antenna. To increase the energy transferred and to provide discrimination against undesirable signals and interference, the coil is usually subjected to resonance with a capacitor at the frequency of the interrogation signal carrier. Other multi-bit data tagging systems employ conventional high-frequency radio technology or technologies based on surface acoustic waves or magnetostriction phenomena. A particular system described in U.S. Pat. No. 6,144,300 uses markers or magnetic labels together with a variety of techniques by means of which such labels can be interrogated. As an example, the label or magnetic marker can be characterized as having a plurality of discrete, magnetically active regions, in a linear array, which provide an interrogation method of a magnetic label or tag. within a predetermined interrogation zone. Many of the methods described above are used as devices and / or methods to prevent theft, for use with storage containers or "jewelry boxes" used to store compact discs (CDs) and digital video discs (DVDs for its acronym in English). The U.S. patent No. 5,573,120 provides a description of such storage containers and is incorporated herein for reference. The publication of the U.S. 2004/0008613 discloses storage containers with a barcode or an RFID tag attached to a wall of the container. A disadvantage for the methods described above is that they typically require the attachment of a label or a magnetic tag or identifier to an article, which can be removed. Many methods have been contemplated to make removal difficult, but nevertheless, once labels or tags are removed, systems based on their presence fail. Accordingly, there is a need in the art to provide a data and / or security system for items that can be stolen, in which it could be difficult, if not impossible, to remove a marker without seriously damaging the article.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides composite materials including a resin containing a polymer, obtained by the polymerization of a monomer mixture containing at least one polymerizable monomer, and a magnetic material. The present invention also provides raw materials in sheet form, made of the composite material described above. The present invention further provides a storage container incorporating a box containing elements including a lower tray and a cover, the cover can be moved between the open and closed, alternative positions, relative to the lower tray, wherein at least a portion of at least one of the components includes the composite material described above. The present invention is also directed to the methods of manufacturing the composite material described above, which may include mechanical grinding of the magnetic material in a resin or using volume, suspension, emulsion, mini-emulsion or micro polymerization techniques. emulsion, wherein the resin is formed by the polymerization of a monomer mixture containing at least one polymerizable monomer in the presence of the magnetic material. The present invention is further directed to a method of manufacturing the containers described above, whereby the sheet-like raw material, described above, is molded or shaped in the form of one or more of the lower tray and / or the cover, of the box described above. The present invention further provides a method for preventing theft of an article that includes the provision of the container described above containing the composite material, the application of a magnetic field to an interrogation zone, causing the movement of the container in the interrogation zone , and detect a magnetic response resulting from the movement of the container in the interrogation zone. BRIEF DESCRIPTION OF THE FIGURE Figure 1 is an exploded perspective view of a compact disc storage container according to the present invention. DETAILED DESCRIPTION OF THE INVENTION In contrast to the operative examples or where otherwise indicated, all the numbers or expressions that refer to the amounts of the ingredients, the reaction conditions, etc., used in the specification and claims, they will be understood as which are modified in all cases by the term "approximately". Accordingly, unless otherwise indicated, the numerical parameters described in the following specification and the appended claims are approximations that may vary depending on the desired properties, which are desired in the present invention. At a minimum, and not as an attempt to limit the application of the doctrine of equivalents with respect to the scope of the claims, each numerical parameter must be interpreted at least in view of the number of significant digits represented and by the application of ordinary techniques rounding. Regardless of the numerical ranges and the parameters describing the broad scope of the invention are approximations, the numerical values described in the specific examples are reported as precisely as possible. Whatever numerical values, however, inherently contain certain errors that necessarily result from the standard deviation found in their respective test measurements. Also, it should be understood that any numerical range described herein is proposed to include all subintervals assumed there. For example, a range of "1 to 10" is proposed to include all subintervals between and including the minimum value described of 1 and the value maximum described of 10; that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. Because the numerical ranges described are continuous, they include each value between the minimum and maximum values. Unless expressly stated otherwise, the various numerical ranges specified in this application are approximations. When used herein, the terms "(meth) acrylic" and "(meth) acrylate" are meant to include both acrylic and methacrylic acid derivatives, such as the corresponding alkyl esters frequently referred to as acrylates and (meth) acrylates, which is understood to encompass the term (meth) acrylate. "When used herein, the term" polymer "is understood to include, withlimitation, oligomers, homopolymers, copolymers, and graft polymers.When used herein, the term" thermoplastic " "refers to polymeric and / or resinous materials and adjuvants and / or additives mixed therein that can be shaped by the application of heat and / or pressure and that can be repeatedly softened by heating and hardened again during cooling. to be specified otherwise, all molecular weight values are determined using gel permeation chromatography (GPC) (by its acronym in English) using the appropriate polystyrene standards. Unless expressly stated otherwise, the molecular weight values indicated herein are average, weighted (Mw) molecular weights. For use herein, the term "magnetic material" refers to materials, non-limiting examples are metals, which may be magnetized or attracted by a magnet and / or are capable of producing an external magnetic field to itself and / or are capable of producing a change or a measurable magnetic signal when placed in a magnetic field. When used herein the term "magnetic response" refers to the effect that a magnetic material has on a magnetic field. As a non-limiting example, magnetic materials have a relative permeability greater than that which can be amplified in a magnetic field in a measurable manner. The present invention provides a composite material that includes a resin and a magnetic material. In one embodiment of the invention, the magnetic material is present as dispersed particles within the resin. The resin contains a polymer obtained by polymerization of a monomer mixture containing at least one polymerizable monomer. Any polymerizable monomer suitable can be used in the invention. When used herein, the term "polymerizable monomer" refers to a molecule that contains a double bond that produces additional polymerization reactions when exposed to a source of free radicals. Non-limiting examples of polymerizable monomers include linear, branched, or cyclic, aliphatic or aromatic C2-C32 molecules, containing a non-conjugated double bond, C2-C32 aliphatic molecules containing two conjugated double bonds, linear, branched esters , or cyclic, aliphatic or aromatic of C? -C32 of (meth) acrylic acid, vinyl esters of linear, branched, or cyclic, aliphatic or aromatic C2-C32 carboxylic acids, or cyclic carboxylic acids, C3 aliphatic molecules -C32 containing an allyl or methallyl group, (meth) acrylonitrile, maleic anhydride, linear, branched, or cyclic, aliphatic or aromatic mono- or di-esters of C? ~ C32 of maleic acid or itaconic acid, maleimide, and the like . In one embodiment of the invention, the polymerizable monomer is selected from vinyl aromatic monomers; linear or branched olefins of C2 to C22; linear, cyclic or branched esters of Ci to C22 of (meth) acrylic acid; maleic acid, its anhydrides or the mono- or diesters of the same linear, cyclic or branched Ci to C22; maleimide, itaconic acid, its anhydrides or the mono- or diesters of the same linear, cyclic or branched Ci to C22, fumaric acid or the mono- or diesters of the same linear, cyclic or branched Ci to C22; linear, branched or cyclic conjugated dienes of C4 to C22, (meth) acrylonitrile and combinations thereof. In one embodiment of the invention, the vinyl aromatic monomers are selected from styrene, p-methyl styrene, α-methyl styrene, tertiary butyl styrene, dimethyl styrene, brominated or chlorinated, nuclear derivatives, thereof and combinations thereof. In a particular embodiment of the invention, the monomer mixture includes styrene. The styrene may be present in the monomer mixture at a level of at least 25, in some cases at least 30, and in other cases at least 35 parts by weight based on the weight of the monomer mixture. Styrene can also be present in the monomer mixture at a level of up to 100, in some cases up to 90, in other cases up to 80, in some cases up to 70, in other cases up to 65, in some cases up to 60, in other cases up to 55 and in particular situations up to 50 parts by weight based on the weight of the monomer mixture. The amount of styrene is determined based on the physical properties desired in the composite material resulting. The amount of styrene in the monomer mixture can be any value described above or can vary between any of the values described above. In one embodiment of the invention, the olefins in the monomer mixture include ethylene, propylene, 1-butene, isobutylene, 2-butene, diisobutylene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-octene, 2-octene, 3-octene, and combinations thereof. During the polymerization, the repeating units derived from the olefins may be present in the form of homopolymers, copolymers, and / or block polymers containing repeat units resulting from the polymerization of one or more of the olefins. In one embodiment of the invention, the polymer can have a weighted average molecular weight of at least 1,000, in some cases of at least 5,000 in other cases of about 10,000, in some situations of at least 15,000, in other situations of at least 25,000 , in some cases of at least 50,000 and in other cases not less than about 75,000, and can be up to 500,000, in some cases up to 400,000 and in other cases up to 300,000. The weight average molecular weight of the polymer can be any polymer or can vary between any of the values described above. In another embodiment of the invention, the resin includes an elastomeric polymer. In a particular embodiment of the invention, the resin is characterized in that it has a continuous phase and a dispersed phase. The continuous phase contains the polymer described above which results from the polymerization of the monomer mixture and the dispersed phase contains at least a portion of the elastomeric polymer. In a particular embodiment of the invention, the dispersed phase is present in the composite at a level of at least 2 parts by weight, in some cases at least 3 parts by weight, in other cases at least 5 parts by weight, and in some situations at least 10 parts by weight based on the weight of the composite material. Also, the dispersed phase may be present in the composite at a level of up to 50 parts by weight, in some cases up to 45 parts by weight, in other cases up to 40 parts by weight, in some cases up to 35 parts by weight. weight, in other cases up to 30 parts by weight, and in particular situations up to 25 parts by weight based on the weight of the composite material. The amount of the dispersed phase is determined based on the physical properties desired in the resulting remaining material. The amount of the dispersed phase in the composite material can be any value described above or can vary between any of the values described above. In one embodiment of the invention, the polymer Elastomeric can have a weighted average molecular weight of at least 1,000, in some cases of at least 5,000, in other cases of approximately 10,000, in some situations of at least 15,000, in other situations of at least 25,000, in some cases of at least 50,000 and in other cases no less than about 75,000, and can be up to 500,000, in some cases up to 400,000 and in other cases up to 300,000. The weight average molecular weight of the elastomeric polymer can be any value or can vary between any of the values described above. In one embodiment of the invention, the elastomeric polymer is selected from the homopolymers of butadiene or isoprene; random, block, AB diblock copolymers, or ABA triblock copolymers of a conjugated diene with an aryl monomer and / or (meth) acrylonitrile; natural rubber; and combinations thereof. In a more specific embodiment, the elastomeric polymer may include one or more block copolymers selected from the diblock and triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene, styrene-isoprene-styrene, ethylene-acetate of partially hydrogenated vinyl, styrene-isoprene-styrene, and combinations thereof. In an additional mode, the dispersed phase desirably contains one or more of the block copolymers, which may be block rubber copolymers. Desirably, the block copolymers include one or more diblock or triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene, styrene-isoprene-styrene and partially hydrogenated styrene-isoprene-styrene. Examples of suitable block copolymers include, but are not limited to, STEREON® block copolymers available from the Firestone Tire and Rubber Company, Akron OH; the ASAPRENE ™ block copolymers available from Asahi Kasei Chemicals Corporation, Tokyo Japan; the KRATON® block copolymers available from Kraton Polymers, Houston, TX; and the VECTOR® block copolymers available from Dexco Polymers LP, Houston, TX. In one embodiment of the invention, the block copolymer is a compound of linear or radial blocks. In one embodiment of the invention, the block copolymer has a weight average molecular weight of at least 50,000 and in some cases not less than about 75,000, and may be up to 500,000, in some cases up to 400,000 and in other cases up to 300,000 The weight average molecular weight of the block copolymer can be any value or can vary between any of the values described above. In another embodiment of the invention, the copolymer of blocks is a styrene-butadiene-styrene or styrene-isoprene-styrene triblock copolymer having a weight average molecular weight from about 175,000 to about 275,000. In a preferred embodiment of the invention, at least some of the polymers of the continuous phase are grafted onto the block copolymer in the dispersed phase. In one embodiment of the invention, the dispersed phase is present as discrete particles dispersed within the continuous phase. In addition to this embodiment, the volume average particle size of the dispersed phase in the continuous phase is at least about 0.1 μm, in some cases at least 0.2 μm and in other cases at least 0.25 μm. Also, the volume average particle size of the dispersed phase in the continuous phase can be up to about 2 μm, in some cases up to 1.5 μ and in other cases up to 1 μm. The particle size of the dispersed phase in the continuous phase can be any value described above and can vary between any of the values described above. In another embodiment of the invention, the dimensional ratio of the discrete particles is from about 1, in some cases from at least about 1.5 and in other cases from at least about 2 and may be from about 5, and in some cases up to about 4 and in other cases from about 3. When the dimensional ratio of the scattered particles is too large, the resulting thermoplastic sheet is cloudy and not clear or transparent. The dimensional relationship of the scattered discrete particles can be any value or range between any of the values described above. As a non-limiting example, the dimensional relationship can be measured by electron scanning microscopy or by light scattering. The particle size and the dimensional relationship of the dispersed phase can be determined using the scattering of light at reduced angles. As a non-limiting example, a Diffraction Particle Size Analyzer with Laser Beam Model LA-910 available from Horiba Ltd., Kyoto, Japan, can be used. As a non-limiting example, a sample of rubber modified polystyrene can be dispersed in methyl ethyl ketone. The suspended rubber particles can then be placed in a glass cell and subjected to light scattering. The scattered light of the particles in the cell can be passed through a lens of the capacitor and converted into electrical signals by the detectors located around the cell of the sample. As a non-limiting example, a He-Ne laser beam and / or a tungsten lamp may be used to supply light with a shorter wavelength. The particle size distribution can be calculated based on the scattering theory of Mye of the angular measurement of scattered light. The magnetic material, as described above, can be any material that has the properties of attracting iron and / or of producing an external magnetic field thereto. In one embodiment of the invention, the magnetic material is present as dispersed particles within the resin. In one embodiment of the invention, the magnetic material contains one or more compounds containing atoms or molecules selected from Ba, Fe, Ru, Co, Ni, Cd, Cr, Mo, Mn, W, V, Nb, Ta, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, alloys thereof, and combinations thereof. Also, the magnetic material may optionally include silicon, nitrogen, sulfur, and / or oxygen atoms, non-limiting examples are oxides, nitrides, nitroxides, silicates, carbonates and / or sulfides of one or more of the aforementioned magnetic materials. Additional non-limiting examples include ferric oxide; ferrous oxide; barium ferrite, tert-butyl-aryl nitroxide, aryl-aryl nitroxide, nitronyl nitroxide, and / or imino nitroxide coordinated with Mn, Fe, and / or Ru; iron nitride; calcium-iron silicate; calcium silicate- manganese-iron, iron sulfide; iron carbonate. In one embodiment of the invention, the magnetic material can be a magnetite, macchiemite, goethite and / or ferrite according to the formula MOFE203, wherein M is selected from Mn, Co, Ni, Cu, Zn, Mg, Cd, and combinations thereof. In another embodiment of the invention, the magnetic material may include a complex of a paramagnetic organic ligand for multiple paramagnetic, transition metal ions. In a further embodiment of the invention, the magnetic material may be present in the resin as discrete dispersed particles within the polymer. In addition to this embodiment, the volume average particle size of the particles of the volumetric material in the polymer can be at least about 0.001 μm, in some cases at least about 0.01 μm, in other cases at least about 0.1 μm , in some cases at least 0.2 μ and in other cases at least 0.25 μm. Also, the volume average particle size of the particles of the magnetic material dispersed in the polymer can be up to about 10 μm, in some cases up to 5 μm and in other cases up to 1 μm. The particle size of the particles of the magnetic material dispersed in the polymer can be of any value described above and can be vary between any of the values described above. In another embodiment of the invention, the dimensional relationship of the particles of the magnetic material can be at least about 1, in some cases at least 1.5 and in other cases at least about 2 and can be up to about 5, in some cases cases of up to about 4 and in other cases of up to about 3. When the dimensional ratio of the particles of the magnetic material is too large, the resulting thermoplastic sheet may be cloudy and not clear or transparent. The dimensional relationship of the particles of the magnetic material can be any value or range between any of the values described above. As a non-limiting example, the particle size and / or the dimensional relationship can be measured by electron scanning or light scattering microscopy. In one embodiment of the invention, the magnetic material may be present in the composite at a level of at least about 0.001, in some cases at least 0.01, in other cases at least 0.1, in some situations of at least 1, and in other situations of at least 2 weight percent of the composite material. Also, the magnetic material can be present at a level of up to about 25, in some cases up to 20, in others cases of up to 15, and in some cases up to 10 percent by weight of the composite material. The amount of the magnetic material present in the composite material will be an amount sufficient to provide desirable magnetic properties as described herein, but not so much as to cause the physical properties of the composite material not to satisfy the intended use of the material. The amount of the magnetic material in the composite material can be any value or can vary between any of the values described above. In one embodiment of the invention, the magnetic material is present at a level sufficient to allow the composite to be detected when it is introduced into the magnetic field or into the interrogation zone as described below by the provision of a magnetic response that is can measure In a further embodiment of the invention, the type and amount of the magnetic material is selected to provide a desired coercivity to the composite material. The desired coercivity is determined based on the planned use of the composite material. When used here, the term "coercivity" refers to a measure of how difficult it is to encode information about the composite material, typically measured in Oersteds (Oe) and can be determined in accordance with ISO / IEC 7811. The coercivity of the Composite material can be at least 50, in some cases at least 100, and in other cases at least 200 Oe.

Also, the coercivity of the composite material can be up to 4,000, in some cases up to 3,500 and in other cases up to 3,000 Oe. The coercivity of the composite material can be any value or range between any of the values described above. In the embodiments of the invention, the composite material can be a low coercivity material. As such, the coercivity of the magnetic material is less than 1,000, in some cases less than 900, and in other cases less than 750 Oe. In the embodiments of the invention, the composite material can be a high coercivity material. As such, the coercivity of the magnetic material is greater than 1,000, in some cases at least 1,500, and in other cases at least 2,000 Oe. In a particular embodiment of the invention, the composite material includes at least one styrene-based polymer (homopolymer or copolymer) and the magnetic material includes an alloy containing silicon, cobalt, nickel, and / or iron. The resin described above can be formed by the formation of a monomer mixture as described above, in which one or more elastomeric polymers they can be dissolved and / or dispersed, devoid of air or sprayed with nitrogen, while mixing and adding an appropriate free radical polymerization initiator at a temperature suitable for effecting free radical polymerization, optionally in the presence of the magnetic material. In one embodiment of the invention, when an elastomeric polymer is included, at least some of the monomer mixtures react with the unsaturated groups in the elastomeric polymer to provide the graft to the elastomeric polymer. The methods for polymerizing the monomer mixture and the dispersed phase are already known in the art. Examples of such methods are described in, as non-limiting examples, U.S. Nos. 4,772,667 to Bil et al., And 5,891,962 to Otsuzuki et al., The relevant portions of which are incorporated herein by reference. Desirably, the manufacturing conditions are adapted to provide thermoplastic compositions, thermoplastic sheets and thermoplastic articles having the properties described herein. The composite material can be prepared as described above using bulk, suspension, emulsion, mini-emulsion or micro-emulsion polymerization techniques as are known in the art. Either of the polymerization initiator, suitable, can be used in the invention. Suitable non-limiting examples of the polymerization initiators include dibenzoyl peroxide, diterc-butyl peroxide, dilauryl peroxide, dicumyl peroxide, didecanoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, butyl, tert-butyl peroxyacetate, or butyl peroxybenzoate and also azo compounds, for example, 2'2'-azobis (2,4-dimethylvaleronitrile), 2,2-azobis- (isobutyronitrile), 2,2'-azobis (2,3-dimethylbutyronitrile), 1,1'-azobis- (1-cyclohexanonitrile), as well as combinations of any of the foregoing. In one embodiment of the invention, adjuvants such as pigments or dyes or both, can be included in the resin. As non-limiting examples, the pigments and / or dyes may include titanium dioxide. The pigments and / or dyes, when added to the resin, will generally lead to an opaque sheet. A clear or transparent sheet can be defined having turbidity values of 10% or less, and it is already known to those skilled in the art that the turbidity values do not apply to an opaque sheet. When used herein "pigments and / or dyes" refers to any suitable organic and inorganic pigment or any organic dye. Suitable pigments and / or dyes are those that do not have an impact adverse on the physical properties of the thermoplastic sheet. The pigments and / or dyes may include magnetic materials. Non-limiting examples of the organic pigments include titanium dioxide, iron oxide, zinc chromate, calcium sulfide, chromium oxides and sodium aluminum silicate complexes. Non-limiting examples of the organic type pigments include azo and diazo pigments, carbon black, phthalocyanines, quinacridone pigments, perylene pigments, isoindolinone, anthraquinones, thioindigo and solvent dyes. In another embodiment of the invention, the adjuvants may include one or more additives selected from lubricants, fillers, light stabilizers, thermal stabilizers, surface active agents, and combinations thereof. These additives, when added to the thermoplastic composition will generally lead to an opaque sheet. Suitable fillers are those that do not have an adverse impact, and in some cases improve, the desirable physical properties of the thermoplastic sheet. Suitable fillers include, but are not limited to, calcium carbonate in the milled and precipitated form, barium sulfate, talc, glass, clays such as kaolin and montmorrillonites, mica, and combinations thereof.

Suitable lubricants include, but are not limited to, ester waxes such as glycerol types, esters of polymer complexes, ester waxes of the oxidized polyethylene type and the like, metal stearates, such as barium, calcium, magnesium, zinc and aluminum stearate, and / or combinations thereof. In general, any conventional ultraviolet (UV) stabilizer known in the art can be used in the present invention. Non-limiting examples of suitable UV light stabilizers include 2-hydroxy-4- (octyloxy) -benzophenone, 2-hydroxy-4- (octyloxy) -phenyl-phenyl-methanone, 2- (2'-hydroxy) 3, 5 '-di-teramylphenyl) -benzotriazole and the family of stabilizers available under the trademark TINUVIN® from Ciba Specialty Chemicals Co. , Tarrytown, NY. Thermal stabilizers that can be used in the invention include, but are not limited to, hindered phenols, non-limiting examples are the IRGANOX® stabilizers and the antioxidants available from Ciba Specialty Chemicals. When any or all of the suitable adjuvants are used in the present invention, they can be used at a level of at least 0.01 weight percent, in some cases up to at least 0.1 weight percent and in other cases at least 0.5 and up to 10 percent by weight, in some cases up to 7.5 percent by weight, in other cases up to 5 percent by weight, and in some situations up to 2.5 percent by weight of the composite material. The amount, type and combination of the adjuvants used will depend on the particular properties desired in the composite material. The amount of any single adjuvant, or any combination of adjuvants may be of any value described above and may vary between any of the values recited above. The mixing and complete dispersion of the additive in the resin is important, but otherwise the processing conditions are similar to those typically employed in the art. In the embodiments of the invention, the magnetic material is incorporated into the composite material as the powders of micron size and / or nanometer size. As such, the magnetic material can have a particle size of at least 10 ~ 6 mm, in some cases of at least 10"5 mm, in other cases of at least 10" 4 mm and in some cases of at least 10 ~ 3 mm. Also, the magnetic material can have a particle size of up to 1 mm, in some cases up to 0.1 mm, and in other cases up to 0.01 mm. The size of the magnetic particles can be any value described above or can vary between any of the values described above. In one embodiment of the invention, the surface modifying additives may be included in the composite material and / or the magnetic material. The surface modified particles can be prepared by: forming an aqueous dispersion of particles comprising the magnetic material, and one or more surface active agents; subject the dispersion to mixing conditions with high shear; and combining the dispersion with an aqueous solution comprising a surface modifying agent. In one embodiment of the invention, the surface modifying agent can include polyvinyl alcohol, natural waxes, polyolefin waxes, white oil and combinations thereof. More particularly, the waxes used in the present invention, at atmospheric pressure, are typically solid at 20 ° C and below this value, in some cases at 25 ° C and below this value, and in other cases at 30 ° C and below this value, and are liquid at 125 ° C and above this value, in some cases 150 ° C and above this value, and in other cases 200 ° C and above this value. The physical properties of the waxes used in the present invention are selected to provide the desirable properties in the present composition as described herein. In one embodiment of the invention, the waxes are selected from natural and / or synthetic waxes. As such, the waxes used in the present invention may be one or more materials selected from alkyl, alkenyl, aryl, alkaryl, or aralkyl, linear, branched, or cyclic alcohols from Cio to C32, in some cases from Ci2 to C32, in some cases of C? 4 to C32, and in other cases of C? 5 to C32, linear, branched or cyclic C? 0 to C32 carboxylic acids of alkyl, alkenyl, aryl, alkaryl or aralkyl, in some cases C? 2 to C32, in some cases from C? 4 to C32, and in other cases from Cie to C32 and / or their corresponding metal and ammonium salts and linear alkyl, alkenyl, aryl, alkaryl, or aralkyl esters, branched or cyclic from Ci to C32, in some cases from Ci2 to C32, in some cases from C? 4 to C32 and in other cases from Ci6 to C32, linear, branched alkyl, alkenyl, aryl, alkaryl, or aralkyl hydrocarbons or cyclics from Cío up to C32, in some cases from C? 2 to C32, in some cases from C? 4 to C32, and in other cases from C? 6 to C32, polyethylene, polypropylene, polyester, and combinations thereof, provided that they satisfy a combination of liquid and solid temperatures as described above. The white oils used in this composition are typically liquid at atmospheric pressure and at 20 ° C and above this value, in some cases 15 ° C and above this value, in other cases 10 ° C and above this value, in some cases 5 ° C and above of this value and in other cases 0 ° C and above this value. As such, the white oils used in the present invention can be one or more materials selected from straight, branched or cyclic alkyl hydrocarbons from Cio up to C32, in some cases from C? 2 to C24, and in other cases from C? 2. up to C22, provided that the physical properties described above are present. In another embodiment of the invention, the surface modifying agent may be present in the aqueous solution at a level of at least about 0.01, in some situations of at least about 0.05, in some cases at least 0.1, in other instances of at least 0.25, in some cases at least 0.5 and in other cases at least 1% by weight. Also, the surface modifying agent may be present in the aqueous solution at a level of up to about 10, in some cases up to 7.5, and in other cases up to 5% by weight based on the weight of the aqueous solution. In one embodiment of the invention, the resin is formed by the polymerization of a monomer mixture, as described above, in the presence of the material magnetic to form the composite material. In this embodiment, the magnetic material is added to the monomer mixture, which is then polymerized as described above. In a particular embodiment of the invention, the composite material is prepared by a suspension polymerization method that includes: surface modifying particles that include the magnetic material to provide surface modified particles; combining the surface modified particles as a monomeric composition including styrene and optionally other monomers as described above, and a polymerization initiator to provide a polymerization mixture; polymerizing the polymerization mixture to provide a suspension of composite beads; and recover the composite beads. In a particular embodiment of the invention, the polymerization can be carried out using the methods described in the provisional application U.S. No. Ser. 60 / 679,468, the relevant portions of which are incorporated herein for reference, wherein a dispersion of droplets containing the monomeric phase is formed by the pressure atomization of the phases of a monomer to form a dispersion of organic droplets. The magnetic material can optionally be included in the monomeric phase. In another embodiment of the invention, the composite material is prepared by mechanically grinding the magnetic material in the resin already formed. In one embodiment of the invention, mechanical milling may include the composition in the molten phase. In another embodiment of the invention, mechanical milling may include milling using the equipment selected from batch mixers, single screw extruders, twin screw extruders and combinations thereof. In a further embodiment of the invention, mechanical grinding may include milling in a ball mill using a weight ratio of the beads to the composite material of at least 2: 1, in some cases at least 3: 1 and in other cases of at least 5: 1 and can be up to 25: 1, in some cases up to 20: 1, in other cases up to 15: 1, and in some situations up to 10: 1. The weight ratio of the stainless steel balls to the composite material can be any value or range between any of the values described above. The middle balls may be composed of any suitable materials. The materials of the Medium balls, suitable, include, but are not limited to steel, stainless steel, iron, lead, antimony, bronze, copper, nickel, porcelain, ceramics, rock crystal, chrome, and combinations and alloys thereof. The middle balls can be at least 0.1, in some cases at least 1 and in other cases at least 2 mm in diameter and can be up to 150, in some cases up to 100, in other cases up to 50, in some situations up to 40, in other situations up to 30, in some cases up to 25, and in other cases up to 20 mm in diameter. The medium beads used in the ball mills can be of any size or range between any of the sizes indicated above. In one embodiment of the invention, the composite material can be formed into a thermoplastic sheet. The present thermoplastic sheet can be prepared by working the composite material described above to form the thermoplastic sheet. Desirably, the composite material, in the company of any adjuvants and / or other desired polymers, are combined, can be mixed on a hot grinding roll or other composite equipment, and the mixture cooled, granulated and extruded into a sheet. The formulation can be mixed in extruders, such as single screw or twin screw extruders, compound and extruded into pellets, which can be then remanufactured. The extruder can also be used to extrude the composite material such as a tube, a sheet, a film or a profiled material. The composite material can be extruded at a temperature that allows the formation of a sheet with the desired physical properties. In one embodiment of the invention, the composite material is extruded from at least about 121 ° C (250 ° F), in some cases to at least about 149 ° C (300 ° F), in other cases at least about 204 ° C (400 ° F), in some cases at least about 232 ° C (450 ° F) and up to about 288 ° C (500 ° F), in some cases up to about 260 ° C (550 ° F) in some cases up to about 316 ° C (600 ° F), and in other cases up to about 326 ° C (650 ° F). The extrusion temperature will depend on the composition of the materials used and the physical properties desired in the resulting sheet. The extrusion temperature can be any temperature or temperature range between any of the temperatures indicated above. The films or sheets can be oriented uniaxially or biaxially either during extrusion or after such processing by reheating and stretching. The films or sheets can be treated with additives after forming, such as with adhesives for sealing with heating, appropriate, coatings for ink, printing, label and similar adhesions. In one embodiment of the invention, the thermoplastic sheet may have a thickness of at least about 0.05 mm, in some cases at least about 0.1 mm and in other cases at least about 0.25 mm and may be up to about 5 mm, in some cases up to approximately 4 mm, in other cases up to approximately 5 mm, in some cases up to approximately 7.5 mm and in other cases up to approximately 10 mm. The thickness of the thermoplastic sheet can vary depending on its proposed use. The thickness of the thermoplastic sheet can be any value or can vary between any of the values described above. Once formed, the printing can be applied to the present thermoplastic sheet. Typically, a printed layer is applied on at least a portion of a surface of the thermoplastic sheet. The printed layer can be applied using methods known in the art, not limited to, offset printing, gravure printing, stamping, and the like. In one embodiment of the invention, the surface of the sheet can be treated prior to printing. Any suitable surface treatment that improves the quality of the printing and / or improves the print quality of the surface of the sheet, it can be used. As a non-limiting example, the surface treatment may be an oxidative surface treatment, a non-limiting example is the discharge of a corona arc, which may be used to improve the receptivity of the ink prior to printing. As a non-limiting example, the treatment with a crown arc can be used using one of the UNI-DYNE® crown arc systems available from Corotec Corporation, Farmington, CT. Desirably, the printed layer includes an ink composition. Any suitable ink composition known in the art can be used, as long as the composition of the ink is substantial with respect to the thermoplastic sheet. The invention also provides thermoformed articles made from a thermoplastic sheet. Non-limiting examples of such items include packaging, such as jewelry boxes for CDs and DVDs, as well as any packaging where it may be advantageous to incorporate a magnetic material into the package, such as to prevent theft. As such, packaging or containers for jewelery, watches, electronic devices, computers, stereo equipment, video equipment, and the like can be made from the present composite material and the thermoplastic sheets of the material. compound. In addition, the thermoplastic sheets of the present composite material can be used in a multilayer thermoplastic composite including one or more layers of the substrate and one or more layers made of the composite material of the invention and one or more layers containing another thermoplastic material , such multi-layer composite materials can be thermoformed into articles as described above. In one embodiment of the invention, the other thermoplastic material may be selected from impact modified polystyrene, copolymers comprising styrene and maleic anhydride and optionally an alkyl (meth) acrylate, rubber modified copolymers comprising styrene and maleic anhydride and optionally a (meth) alkyl acrylate, polyolefins, poly (meth) acrylates, and combinations thereof. In one embodiment of the invention, the composite material can be formed in one or more parts of a storage container. As such, the present invention also provides a storage container that includes a box that includes a lower tray and a cover, the cover being movable between the open and closed, alternative positions, relative to a bottom tray, wherein minus a portion of at least one of the Bottom tray and / or cover includes the composite material described above. More specifically, once the desired temperature is reached, the thermoplastic sheet can be shaped into the desired shape by known processes such as thermoforming aided by plugging wherein a plug pushes the thermoplastic sheet towards a mold of the desired shape. The air pressure and / or a vacuum can also be used to mold the desired shape. In a particular embodiment of the invention, a label can be placed in the thermoforming machine prior to the formation of the container and is adhered to the container formed. In a further embodiment of the invention, the storage container can be made using injection molding techniques that are known in the art. Figure 1 shows a non-limiting example of one embodiment of the container of the present invention generally at 10, with the components illustrated in a perspective, exploded relationship. It is noted that the container includes a bottom tray 12, a cover or lid 14, and an insert tray generally shown at 16 to be inserted into the bottom tray 12. The lid 14 includes an upper plate 18, a pair of side walls 20 and 22, lugs 24 and 26 fixed to the rear ends of the side walls, spaced tabs 30 extending inwardly from the side walls below the top plate, and hooks 34 and 36 extending inwardly from the lugs. The bottom tray 12 similarly includes front and rear walls 38 and 40, side walls 42 and 44 that extend between them and a bottom floor 46. The floor 46 extends a very short distance beyond the walls 42 and 44 to form the flanges 48 and 50, with which the side walls 20 and 22 of the cover 14 abut in a downward manner when the cover is in a closed position. A pair of holes, 52 and 54, pass through the side walls 42 and 44 at the rear corners thereof to receive the hooks 34 and 36 of the cover 14 therein to provide an oscillating shaft for the movement of the cover in relation to the bottom tray 12. The insert tray 16 includes an upper plate having a circular, central recessed area 64, configured for the storage thereon of a compact disc. The recessed area 64 may engage the insert side walls in the central portions thereof so that a disc hangs, over the recessed area, only a fractional distance, over the central portions of the side walls. The disc then engages in the corresponding lower portions of the side walls of the bottom tray 12. The insert tray 16 has side walls 66 and 68 particularly at the corners thereof, that is, where the recessed area 64 does not engage the edges of the top plate 12. At the trailing edge of the insert tray 16 is a step 70 with an elongated tab or element 72 formed on top of it. With the container 10 assembled, the oscillation of the hooks 34 and 36 on the cover 14 relative to the holes 52 and 54 of the lower tray 14 are then carried out below the elongate element 72. When the cover 14 is oscillated to a In the closed position, the elongated element 72 forms a part of the upper surface of the container 10 with the leading edge of the elongate element abutting against the trailing edge of the upper plate 18 of the cover. The lower tray 12 has a pair of notches 84 on both sides of the side walls, and the insert tray 16 has semicircular recessed areas 88 corresponding along both of its side edges 66 and 68 and corresponding to the notches 84. consequently, when the lid 14 is lowered to its closed position, the tabs 30 on the lid will rest downward on the notches 84 and the recessed semicircular areas 88 and thereby retain the insert tray. 16 descendingly against the floor 46 of the lower tray 12. Accordingly, when the box or container 10 is inverted or agitated from back to front, the insert tray 16 and the compact disc (not shown) is not moved in a manner similar from back to front whereby they may collide with the lid 14. The main function of the tabs 30 is thought to be the subject of graphics, ie, a sheet of paper (not shown) with explanatory or advertising information on them, instead of the container and that can be observed through the upper cover, which can be transparent. The insert tray 16 may have a number of very thin, outwardly placed hooks on the side walls thereof, positioned to press-fit into the corresponding internally located holes or openings in the side walls of the lower tray 12. to snap-fit the insert tray 16. In one embodiment of the present invention, either the lower tray 12, or the lid or cover 14, or the insert 16, or all or a portion thereof, they may include a thermoplastic material, such as any of the resins and / or polymers described above that do not contain the magnetic material. The present composite material can then be applied to at least a portion of at least one surface of the tray bottom 12, or cover or lid 14, or insert 16, using rolling techniques, injection molding techniques, or the like, as is known in the art. In a particular embodiment of the invention, the magnetic material is applied to the surface of the lower tray 12, or the cover or lid 14, or the insert 16 as a logo or other markings. According to one aspect of the present invention, the articles including the present composite materials and / or articles that are made of thermoplastic sheets of the present composite material can be used to provide a magnetic marker or label or magnetic element, which in some embodiments of the invention may be characterized as one carrying a plurality of discrete, magnetically active regions in a linear array. As such, the magnetic elements are incorporated directly into the articles during the manufacture of the articles themselves. Accordingly, the items may be used in conjunction with other items or goods, such as retail items, which carry the labels for inventory or security purposes, such as tickets or security passes. In the relatively simple embodiments of the invention, each region magnetically activates an article that can have the same magnetic characteristics; in the more complex modalities, each magnetically active region of an article may possess a different magnetic characteristic, thus making it possible to assemble a large number of labels each with unique magnetic properties and therefore with a unique magnetic identity and signature (ie, the response magnetic when it is processed by a suitable reading device). In one embodiment of the invention, the article may contain portions that include a magnetically soft material (low coercivity), which produces a characteristic signal when excited by an alternating magnetic field, and portions that include a magnetically hard or semi-hard material (high coercivity) ). In embodiments of the invention, an anti-theft system may include a signal generator made of a ferromagnetic material with relatively low coercivity and high permeability for facilitated magnetic detection. The signal generated can depend on the magnetic field and can be detected in the interrogation zone. Also present in the element is a deactivator which includes at least one section containing a ferromagnetic material with a high coercivity connected to the signal generator, which suppresses the generation of the detectable signals when they are magnetized. Sections include at least one ferromagnetic material (often finely distributed) and a polymeric support. In one embodiment of the invention, one of the tray or cover of the storage container may include a composite material having low coercivity and high permeability and the other of the tray or the cover contains a composite material which is a material having a high coercivity. In another embodiment of the invention, a surface of the tray or cover of the storage container has placed on it a composite material having a low coercivity and a high permeability and an opposingly placed surface of the tray or cover contains a composite material which It has a high coercivity material. The composite material can be applied to the surface by rolling or injection molding or as a logo or a mark applied to the surface. In one embodiment of the invention, because the invention can use the relative movement between a tag and an applied magnetic field, it will be appreciated that there will be a time domain match of the output signals from a reading device of the label and the linear dimensions of the magnetically active regions and the linear dimensions of the magnetically active regions of a label and of the gaps between the magnetically active regions. In this sense, the active regions and the gaps between them operate analogously to the elements of an optical bar code (black bars or white gaps between adjacent bars). It follows from this that, just because the variability of the magnetic characteristics in the active regions can be used to generate a part of an "identity" of the tag, there may also be the linear spacing between the magnetically adjacent active regions, such as , in a sandwich, laminated structure of the present composite material. It will be readily understood that a vast number of labels, each with its own unique identity, can thus be produced in accordance with this invention. As well as the labels defined above, the present invention provides a variety of methods useful for detecting the presence of a magnetic label and / or for identifying such a label. One embodiment of the invention provides a method of interrogation of a magnetic label or marker within a predetermined interrogation zone, the label includes a magnetic material of high permeability, for example for the use of the label response to detect its presence and / or to determine its position within the interrogation zone. The interrogation process it may include the step of subjecting the tag sequentially to: (1) a magnetic field sufficient in field strength to saturate the high permeability magnetic material, and (2) a magnetic nullity as defined herein. In one embodiment of the invention, the magnetic nullity is caused to be swept back and forth over a predetermined region within the interrogation zone. The frequency of the scan (that is, the sweep frequency of the magnetic nullity) can be relatively low, for example 1-500 Hz. Conveniently, the field configuration is arranged so that: (a) the magnetic nullity lies in a plane; and (b) the saturation field occurs adjacent to the plane. Another embodiment of the invention provides a method of determining the presence and / or position of a magnetic element within a predetermined interrogation zone, the magnetic element having predetermined magnetic characteristics. The method may include the steps of: (1) establishing within the interrogation zone a magnetic field configuration that includes a relatively small region of zero magnetic field (a magnetic nullity) contiguous with regions where a magnetic field exists enough to saturate the, or a part of, the magnetic element (the saturation field), the relatively small region is coincident with a region through which the magnetic element is passing, or may pass, or is expected to pass; (2) causing the relative movement between the magnetic field and the magnetic element such that the magnetic nullity is caused to pass through at least a part of the magnetic element in a predetermined manner; and (3) detecting the magnetic response resulting from the magnetic element during relative movement. A further embodiment of the invention provides a method of identifying a magnetic element, which has predetermined magnetic characteristics. The method includes the steps of: (1) subjecting the magnetic element to a first magnetic field which is sufficient to induce magnetic saturation in at least a part of the magnetic element; (2) after subjecting the magnetic element to the conditions of the magnetic field (ie, a magnetic nullity), the zero field occupies a relatively small volume and is contiguous with the first magnetic field; (3) causing the relative movement between the applied magnetic field and the magnetic element such that the magnetic nullity is caused to cross at least a part of the magnetic element in a predetermined manner; and (4) detect the magnetic response resulting from the magnetic element during relative movement.

In the identification method defined above, the magnetic element is advantageously caused to traverse an interrogation zone in which the required magnetic conditions are generated. The relative movement between the magnetic element and the magnetic field can be advantageously produced by the sliding of the magnetic field applied on the magnetic element. Alternatively, the relative motion can be achieved by the application of an alternating magnetic field for a generally static magnetic field configuration. The configuration of the field or the field of the material used in the methods defined above can be established by means of two magnetic fields of opposite polarity. This can be conveniently achieved by the use of one or more coils carrying the direct current; or by the use of one or more permanent magnets; or by a combination of coil (s) and magnet (s). Where a coil is used, it can be arranged to carry a substantially constant current to maintain the magnetic nullity at a fixed point. Alternatively, the coil (s) carries / carries a current whose length varies in a predetermined cycle so that the position of the magnetic nullity is caused to oscillate in a predetermined manner called a "fly nullity". A similar arrangement can be used to give a flywheel when both a coil or coils and a permanent magnet are used. According to a further aspect of the present invention, there is provided a method of determining the presence and / or position of a magnetic element, which is characterized by the steps of: (1) applying a magnetic field to a region where the magnetic element is, or is expected to be, the localized magnetic field, including two components of the opposite field, generated by magnetic field sources, which lead to a null field (a magnetic nullity) at an intermediate position with respect to the sources of the magnetic field (such position is known or can be calculated); (2) cause the relative movement between the magnetic field and the magnetic element; and (3) detecting the magnetic response resulting from the magnetic element during relative movement. The relative motion between the magnetic field and the magnetic element can be achieved by the application of an alternating magnetic field of relatively low amplitude superimposed on the DC field. Typically, such an alternating magnetic field of low amplitude has a frequency in the range from 10 Hz to 100 kHz, in some cases from 50 Hz to 50 kHz, and in other cases from 500 Hz to 5 kHz. In one embodiment, the coils carry a current substantially constant to maintain magnetic nullity at a fixed point. In another embodiment, the coils carry a current whose amplitude varies in a predetermined cycle so that the position of the magnetic nullity is caused to oscillate in a predetermined manner. In the methods according to the invention, the detection of the magnetic response of the magnetic element advantageously includes the observation of the harmonic characteristics of the supplied AC field, which are generated by the magnetic element because its magnetization state is altered by the passage to through the magnetic nullity. As indicated above, the system can operate with a zero or very low frequency scanning field, and an HF (high frequency) in the 50 Hz-50 kHz range. This allows good penetration of the signal through most materials including thin metal foils. In addition, international rules allow high fields for transmission at these low frequencies. The embodiments of the invention provide a system of multiple bit data labels, which employ a low frequency inductive magnetic interrogation, and avoid the need for complex cost tags. In accordance with another aspect of the present invention, a method of coding and / or labeling of individual articles within a predetermined set of articles by means of the characteristic of the article data, for example the price of the article and / or the nature of the goods constituting the articles. The method includes the manufacture of articles of the present composite material wherein the articles have a magnetic label or marker that carries a predetermined arrangement of magnetic zones unique to this article or to this article and others that share the same characteristic, for example the price of the article. article or the nature of the genera that constitute the article (the unique magnetic label may be the result of the type and / or the concentration of the magnetic material in the composite material), the label or magnetic marker is susceptible to integration by an applied magnetic field to generate a response indicative of the magnetic properties of the label or marker and therefore indicative of the nature of the article bearing the label or magnetic marker. The present invention will be further described by reference to the following examples. The following examples are only illustrative of the invention and are not intended to be limiting. Unless stated otherwise, all percentages are by weight.

EXAMPLES Example 1 This example describes the use of mechanical milling to make polymer magnetic composite materials, highly dispersed and concentrated, according to the invention. Approximately a 9: 1 ratio of the ground polymer (ZYLAR®-EX, available from NOVA Chemicals Inc., Pittsburgh, PA) with respect to the magnetic powder (iron oxide powder) is added to a stainless steel crucible containing beads. stainless steel. The weight ratio of the stainless steel balls to the powder (polymeric and magnetic) is approximately 14: 1. The grinding with the balls is carried out for 8 hours, and is stopped every 15 minutes for 15 minutes and then restarted to avoid overheating of the sample as generally described in Mat. Sci. Eng. B, 113, 228-235 (2004). A surface modifying additive of polyvinyl alcohol (0.1% by weight of the powder) is added to aid dispersion. An extruded sheet is formed from the resulting powder. The sheet demonstrates magnetic properties. Example 2 This example describes the use of a composition of the molten material to make highly dispersed and concentrated polymeric magnetic composite materials according to the invention. A ratio of approximately 9: 1 of the ground polymer (ZYLAR®-EX) and the magnetic powder (iron oxide powder) with 0.1% by weight of surface-modifying surfactant is added to a batch mixer at 200 ° C. , mixed for 10 minutes, at 200 rpm and extruded to form a sheet. The resulting sheet has good mechanical integrity and demonstrates magnetic activities. Example 3 This example describes a synthetic method for manufacturing the magnetic composite materials according to the invention using polymerization techniques. An aqueous dispersion of magnetic particles (iron oxide, 100 mg in 15 ml of water) and surfactants (100 mg in 5 ml of water) are subjected to sound action for 15 minutes and exposed to mixed with high shear for another 15 minutes. The magnetic and surface modifier solutions are mixed and subjected to the action of sound for another 15 minutes. The mixture of surface modifying aqueous solutions / magnetic particles is added to a 2% by weight aqueous solution of polyvinyl alcohol. The styrene monomer 25 g, and 0.16 g of the benzoyl peroxide initiator are added to the mixture. The system is closed, purged using nitrogen and stirred at 250 rpm. The temperature is elevated at 95 ° C and the polymerization is carried out for 6 hours. The resulting polymer beads are recovered by filtration and successive washes using water and methanol. The beads are extruded to form a sheet, which shows magnetic properties. The present invention has been described with reference to the specific details of the particular embodiments thereof. It is not proposed that such details be considered as limitations on the scope of the invention except with respect to the extent to which they are included in the appended claims. It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the contents of the following claims are claimed as property: 1. A storage container, characterized in that it comprises: a box comprising components that include a bottom tray and a cover, the cover can be moved between the open and closed positions relative to the bottom tray, wherein at least a portion of at least one of the components comprises a composite material including: a resin comprising a polymer obtained by the polymerization of a monomer mixture containing the minus one polymerizable monomer; and a magnetic material. The storage box according to claim 1, characterized in that the polymerizable monomer is selected from the group consisting of aromatic vinyl monomers; linear or branched olefins of C2 to C22; linear, cyclic or branched (meth) acrylic acid esters of Ci to C22; maleic acid, its anhydride or the mono- or diesters thereof, linear, cyclic or branched from Ci to C22; maleimide, itaconic acid, its anhydride or linear mono- or diesters, cyclic or branched Cx to C22 fumaric acid or the mono- or diesters of the same linear, cyclic, or branched Ci to C22; linear, branched or cyclic conjugated dienes from C4 to C22, (meth) acrylonitrile and combinations thereof. 3. The storage box according to claim 1, characterized in that the resin comprises an elastomeric polymer. 4. The storage box according to claim 3, characterized in that the elastomeric polymer is selected from the group consisting of homopolymers of butadiene or isoprene; random, block, AB diblock, or ABA triblock of a conjugated diene with an aryl monomer and / or (meth) acrylonitrile; natural rubber, and combinations thereof. The storage box according to claim 3, characterized in that the elastomeric polymer comprises one or more block polymers selected from the group consisting of diblock and triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene , styrene-isoprene-styrene, ethylene-vinyl acetate, partially hydrogenated styrene-isoprene-styrene, and combinations thereof. 6. The storage box according to claim 2, characterized in that the olefins comprise homopolymers, copolymers, and / or block copolymers containing repeat units resulting from the polymerization of one or more monomers selected from the group consisting of ethylene, propylene , 1-butene, isobutylene, 2-butene, diisobutylene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-octene, 2-octene, 3-octene, and combinations thereof. The storage box according to claim 1, characterized in that the weighted average molecular weight of the elastomeric polymer is from about 1,000 to about 500,000. The storage box according to claim 2, characterized in that the vinyl aromatic monomers are selected from the group consisting of styrene, p-methyl styrene, -methyl styrene, tertiary butyl styrene, dimethyl styrene, brominated or chlorinated derivatives, nuclear, derivatives thereof and combinations thereof. 9. The storage box according to claim 3, characterized in that the resin comprises a continuous phase containing the polymer and a dispersed phase containing the elastomeric polymer. 10. The storage box in accordance with claim 1, characterized in that the magnetic material comprises one or more compounds containing atoms or molecules selected from the group consisting of Fe, Co, Ni, Cd, Cr, Mo, Mn, W, V, Nb, Ta, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, alloys thereof, and combinations thereof. The storage box according to claim 10, characterized in that the magnetic material is selected from the group consisting of a magnetite, a macchiemite, a goethite, a ferrite and combinations thereof. The storage box according to claim 10, characterized in that the magnetic material also comprises boron, silicon, nitrogen, and / or oxygen. The storage box according to claim 1, characterized in that the magnetic material is present at a level from about 0.001 to about 25 weight percent of the composite material. The storage box according to claim 1, characterized in that the magnetic material is present at a level sufficient to allow the storage box to be detected when it is introduced into a magnetic field or interrogation zone. 15. The storage box according to claim 1, characterized in that the composite material it comprises at least one styrene-based polymer and the magnetic material comprises an alloy containing silicon, cobalt, nickel, and / or iron. 16. The storage box according to claim 1, characterized in that the magnetic material is incorporated in the composite material as micronized sized powders or nano-sized powders. 17. The storage box according to claim 1, characterized in that the composite material is prepared by mechanically grinding the magnetic material in the resin. 18. The storage box according to claim 17, characterized in that the mechanical grinding comprises the composition in the molten phase. 19. The storage box according to claim 17, characterized in that the mechanical grinding comprises milling using the equipment selected from the group consisting of batch mixers, single screw extruders, twin screw extruders and combinations thereof. 20. The storage box according to claim 17, characterized in that the mechanical grinding comprises grinding in a ball mill using a weight ratio of the balls with respect to the composite material from 2: 1 to 25: 1. 21. The storage box according to claim 1, characterized in that the composite material is prepared by bulk, suspension, emulsion, mini-emulsion or micro-emulsion polymerization techniques, wherein the resin is formed in the presence of the magnetic material. 22. The storage box according to claim 1, characterized in that the surface modifying additives are included in the composite material. 23. The storage box according to claim 21, characterized in that the composite material is prepared by a suspension polymerization comprising: surface modifying particles comprising the magnetic material; combining the surface modifying particles with a monomeric composition comprising styrene, and a polymerization initiator to provide a polymerization mixture; polymerization of the polymerization mixture to provide a suspension of the composite beads; and the recovery of composite beads. 24. The storage box according to claim 23, characterized in that the particles surface modified are prepared by: the formation of an aqueous dispersion of particles comprising the magnetic material, and one or more surface active agents; subject the dispersion to mixing conditions with high shear; and combining the dispersion with an aqueous solution comprising a surface modifying agent. 25. The storage box according to claim 24, characterized in that the surface modifying agent is selected from polyvinyl alcohol, natural waxes, polyolefin waxes, white oil and combinations thereof. The storage box according to claim 24, characterized in that the surface modifying agent is present in the aqueous solution at a level from about 0.01% by weight to about 10.00% by weight based on the weight of the aqueous solution . 27. A composite material, characterized in that it comprises: a resin comprising a polymer obtained by the polymerization of a monomer mixture containing at least one polymerizable monomer; and a magnetic material dispersed within the resin; wherein the magnetic material is present at a level sufficient to allow the material to be detected when it is introduced into a magnetic field or an interrogation zone. The composite material according to claim 27, characterized in that the polymerizable monomer is selected from the group consisting of aromatic vinyl monomers; linear or branched olefins of C2 to C22; esters of (meth) acrylic acid, linear, cyclic or branched from Ci to C22; maleic acid, its anhydride or mono or diesters thereof, linear, cyclic or branched from Ci to C22; maleimide, itaconic acid, its anhydride or mono or diesters thereof, linear, cyclic or branched from Ci to C22; fumaric acid or mono or diesters thereof, linear, cyclic or branched from Ci to C22; linear, branched, or cyclic conjugated dienes of C4 through C22, or cyclic conjugated dienes, (meth) acrylonitrile and combinations thereof. 29. The composite material according to claim 27, characterized in that the resin comprises an elastomeric material. 30. The composite material according to claim 29, characterized in that the elastomeric polymer is selected from the group consisting of homopolymers of butadiene or isoprene; random, block, AB diblock copolymers, or ABA triblock copolymers of a conjugated diene with an aryl and / or (meth) acrylonitrile monomer; natural rubber; and combinations thereof. 31. The composite material according to claim 29, characterized in that the elastomeric polymer comprises one or more block copolymers selected from the group consisting of diblock and triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene, styrene-isoprene-styrene, ethylene-vinyl acetate, styrene-isoprene-styrene partially hydrogenated, and combinations thereof. The composite material according to claim 28, characterized in that the olefins comprise homopolymers, copolymers, and / or block copolymers containing repeat units resulting from the polymerization of one or more monomers selected from the group consisting of ethylene, propylene, 1-butene, isobutylene, 2-butene, diisobutylene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-octene, 2-octene, 3-octene, and combinations thereof. 33. The composite material according to claim 27, characterized in that the molecular weight Weighted average elastomeric polymer is from about 1,000 to about 500,000. 34. The composite material according to claim 28, characterized in that the vinyl aromatic monomers are selected from the group consisting of styrene, p-methyl styrene, α-methyl styrene, tertiary butyl styrene, dimethyl styrene, brominated or chlorinated derivatives, nuclear, of the same and combinations thereof. 35. The composite material according to claim 29, characterized in that it comprises a continuous phase containing the polymer and a dispersed phase containing the elastomeric polymer. 36. The composite material according to claim 27, characterized in that the magnetic material comprises one or more compounds containing atoms or molecules selected from the group consisting of: Fe, Co, Ni, Cd, Cr, Mo, Mn, W, V, Nb, Ta, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, alloys thereof, and combinations thereof. 37. The composite material according to claim 36, characterized in that the magnetic material is selected from the group consisting of a magnetite, macchiemite, a goethite, a ferrite, and combinations thereof. 38. The composite material according to claim 36, characterized in that the magnetic material further comprises boron, silicon, nitrogen, and / or oxygen. 39. The composite material according to claim 27, characterized in that the composite material is present at a level from about 0.001 to about 25 weight percent of the composite material. 40. The composite material according to claim 27, characterized in that the composite material comprises at least one polymer based on styrene and the magnetic material comprises an alloy containing silicon, cobalt, nickel, and / or iron. 41. The composite material according to claim 27, characterized in that the magnetic material is incorporated in the composite material as powders of micronized size or nano-sized powders. 42. The composite material according to claim 27, characterized in that the composite material is prepared by mechanically grinding the magnetic material in the resin. 43. The composite material according to claim 42, characterized in that the mechanical grinding comprises the composition in the molten phase. 44. The composite material according to claim 42, characterized in that the mechanical grinding it comprises grinding using equipment selected from the group consisting of batch mixers, single screw extruders, twin screw extruders and combinations thereof. 45. The composite material according to claim 42, characterized in that the mechanical grinding comprises grinding in a ball mill using a weight ratio of the balls with respect to the composite material from 2: 1 to 25: 1. 46. The composite material according to claim 27, characterized in that the composite material is prepared by bulk, suspension, emulsion, mini-emulsion or micro-emulsion polymerization techniques, wherein the resin is formed in the presence of magnetic material. 47. The composite material according to claim 27, characterized in that the surface modifying additives are included in the composite material. 48. The composite material according to claim 46, characterized in that the composite material is prepared by a suspension polymerization comprising: surface modifying particles comprising the magnetic material; combining the surface modified particles with a monomeric composition comprising styrene, and a polymerization initiator to provide a polymerization mixture; polymerizing the polymerization mixture to provide a suspension of the composite beads; and recover the composite beads. 49. The composite material according to claim 48, characterized in that the surface modified particles are prepared by: the formation of an aqueous dispersion of particles comprising the magnetic material, and one or more surface active agents; subject the dispersion to mixing conditions with high shear; and combining the dispersion with an aqueous solution comprising a surface modifying agent. 50. The composite material according to claim 47, characterized in that the surface modifying agent is selected from polyvinyl alcohol, natural waxes, polyolefin waxes, white oil and combinations thereof. 51. A thermoplastic sheet, characterized in that it is formed from the composite material according to claim 27. 52. The thermoplastic sheet according to claim 51, characterized in that it is formed by extruding the composite material into a sheet. 53. The thermoplastic sheet according to claim 51, characterized in that it is formed using one or more of a single screw extruder and a twin screw extruder. 54. The composite material according to claim 27, characterized in that it is composed and extruded into pellets and is extruded to form a tube, sheet, film or profiled material. 55. The thermoplastic sheet according to claim 31, characterized in that it has a thickness from about 0.05 mm to about 10 mm. 56. The thermoplastic sheet according to claim 31, characterized in that a print is applied on at least one surface. 57. An article, characterized in that it is formed by the thermoforming of the thermoplastic sheet according to claim 31. 58. The article according to claim 57, characterized in that the article is a package adapted to contain jewelry, watches, electronic devices. , computers, stereophonic equipment, video equipment, compact discs or digital video discs. 59. A multi-layer composite material, characterized in that it comprises one or more substrate layers comprising the composite material according to claim 27 and one or more layers comprising another thermoplastic material. 60. The multi-layer composite material according to claim 59, characterized in that the other thermoplastic material is selected from the group consisting of polystyrene, impact modified polystyrene, copolymers comprising styrene and maleic anhydride and optionally a (meth) acrylate of alkyl, rubber modified copolymers comprising styrene and maleic anhydride and optionally an alkyl (meth) acrylate, polyolefins, poly (meth) acrylates, and combinations thereof. 61. The article according to claim 57, characterized in that it is formed by thermoforming assisted with a plug. 62. A method of interrogation of a label or a magnetic marker within a predetermined interrogation zone, characterized in that it comprises: subjecting the magnetic label consecutively to: (i) a magnetic field with a sufficient intensity of the field to saturate the magnetic label, and (ii) a magnetic nullity; wherein the magnetic label comprises the composite material according to claim 27. 63. An interrogation method of a magnetic label or marker within a predetermined interrogation zone, characterized in that it comprises: subjecting the magnetic label consecutively to: (i) a magnetic field of sufficient intensity in the field to saturate the magnetic label; and (ii) a magnetic nullity; wherein the magnetic label comprises the magnetic container according to claim 1. 64. The method according to claim 63, characterized in that the magnetic nullity is caused to slide back and forth over a predetermined region within the region of question. 65. The method according to claim 63, characterized in that the magnetic nullity has a slip frequency of approximately 1-500 Hz; the magnetic field is arranged so that: (a) the magnetic nullity lies in a plane, and (b) the saturation of the field adjacent to the plane occurs. 66. A method of determining the presence and / or position of a magnetic element within a predetermined interrogation zone, wherein the magnetic element has predetermined magnetic characteristics,characterized in that it comprises: establishing within the interrogation zone a configuration of the magnetic field that includes a relatively small region of a magnetic nullity contiguous with the regions where there is a magnetic field sufficient to saturate at least a part of the magnetic element (saturation field) ), the relatively small region is coincident with a region through which the magnetic element is passing or can pass, or is expected to pass; causing the relative movement between the magnetic field and the magnetic element in such a way that the magnetic nullity is caused to pass through at least a part of the magnetic element in a predetermined manner; and detecting the magnetic response resulting from the magnetic element during relative movement; wherein the magnetic element comprises the storage container according to claim 1. 67. A method of identifying a magnetic element, having predetermined magnetic characteristics, characterized in that it comprises: subjecting the magnetic element to a first magnetic field that is sufficient to induce magnetic saturation in at least a part of the magnetic element; subject the magnetic element to the conditions of the zero magnetic field (a magnetic nullity), the field magnetic zero occupies a relatively small volume and is contiguous with the first magnetic field; causing the relative movement between the applied magnetic field and the magnetic element such that the magnetic nullity is caused to pass through at least a part of the magnetic element in a predetermined manner; and detecting the magnetic response resulting from the magnetic element during relative movement; wherein the magnetic element comprises the storage container according to claim 1. 68. The method according to claim 67, characterized in that the magnetic element is passing through an interrogation zone within which the required magnetic conditions are generated. 69. A method of identifying a magnetic element, which has predetermined magnetic properties, characterized in that it comprises: causing the magnetic element to be introduced into the interrogation zone within which a magnetic field configuration has been established that includes a relatively small magnetic field zero (a magnetic nullity) contiguous with regions where there is a sufficient magnetic field to saturate at least a part of the magnetic element (the saturation field); cause the magnetic element to be moved through the saturation field until it reaches magnetic nullity; causing the relative movement between the magnetic field and the magnetic element in such a way that the magnetic nullity is caused to pass through at least a part of the magnetic element in a predetermined manner; and detecting the magnetic response resulting from the magnetic element during relative movement; wherein the magnetic element comprises the storage container according to claim 1. 70. The method according to claim 69, characterized in that the relative movement between the magnetic element and the magnetic field is produced by the sliding of the applied magnetic field. on the magnetic element. 71. The method according to claim 69, characterized in that the relative movement between the magnetic element and the magnetic field is achieved by the application of an alternating magnetic field to a generally static magnetic field configuration. 72. The method according to claim 69, characterized in that the field configuration is established by two magnetic fields of opposite polarity achieved by the use of one or more coils carrying a direct current; or by the use of one or more permanent magnets; or by the combinations of coil (s) and magnet (s). 73. A method of determining the presence and / or position of a magnetic element, characterized in that it comprises: applying a magnetic field to a region where the magnetic element is, or is expected to be located, the magnetic field including two components opposites of the field, generated by the sources of the magnetic field, which leads to a null field (a magnetic nullity) in an intermediate position with respect to the sources of the magnetic field (such a position is known or can be calculated); cause the relative movement between the magnetic field and the magnetic element; and detecting the magnetic response resulting from the magnetic element during relative movement; wherein the magnetic element comprises the storage container according to claim 1. 74. The method according to claim 73, characterized in that the relative movement between the magnetic field and the magnetic element is achieved by the application of a magnetic field. alternate amplitude relatively low, superimposed on a magnetic field of direct current, where the alternating magnetic field of low amplitude has a frequency in the range of 10 Hz to 100 kHz. 75. The method of compliance with the claim 73, characterized in that the coils carry a substantially constant current to maintain the magnetic nullity at a fixed point. 76. The method according to claim 73, characterized in that the coils carry a current whose amplitude varies in a predetermined cycle so that the position of the magnetic nullity is caused to oscillate in a predetermined manner. 77. A method of coding and / or labeling individual articles within a predetermined set of articles by means of the characteristic data of the articles characterized in that they comprise the manufacture of the articles comprising the composite material according to claim 27 as a label or magnetic marker that carries a predetermined arrangement of unique magnetic zones for this article, or for this article and others that share the same characteristic, the magnetic label or marker is susceptible to interrogation by the applied magnetic field to generate a response indicative of the magnetic properties of the label or marker. 78. A storage container, characterized in that it comprises: a box comprising components that include a lower tray and a cover, the cover can be moved between the open and closed positions, alternatives, relative to the bottom tray, wherein at least the The lower tray and the cover comprise a thermoplastic material, wherein a composite material is applied to at least a portion of at least one surface of a component; and wherein the composite material comprises: a resin comprising a polymer obtained by the polymerization of a monomer mixture containing at least one polymerizable monomer; and a magnetic material. 79. The storage container according to claim 78, characterized in that the composite material is applied by rolling or by injection molding. 80. The storage container according to claim 78, characterized in that the composite material is applied as a logo or a mark. 81. The storage container according to claim 1, characterized in that one of the tray or cover comprises a composite material that it has a low coercivity and a high permeability and the other of the tray or cover comprises a composite material which is a material having a high coercivity. 82. The storage container according to claim 1, characterized in that a surface of the tray or cover has placed on it a material or compound having a low coercivity and a high permeability and a surface placed opposite the tray or cover it comprises a composite material having a high coercivity.